Electrical Detectives..Put on your thinking cap

MickLane

Cadet
Joined
May 6, 2004
Messages
19
OK, folks. Here is the scenario. This year when I put my fishing boat (Sea Nymph Great Lakes Special, 90 hp outboard) in the water for opening day of bass fishing, it ran fine and everything was good. But I had one problem. My Garmin fishfinder/GPS unit would run fine and then power down after a few minutes. After opening day, my schedule went berserk and I did not get a chance to put it back in the water until yesterday. It ran fine, but when I went to turn on the lights at dusk, they came on for a second and then went out. No amount of prodding or reinserting them would get them to come on. I pulled the boat, and today I went out to track down the problem. Before I started, I put the lights in the fore and aft sockets, walked up and switched them and they came on fine in both positions. Thinking it might be related to when the engine is running, I put the earmuffs on, turned on the water, and started the engine. The lights were fine. Worked in both the running and anchored switch positions. So I put the boat in the water to go troll for walleye. First thing is the Garmin would not even come on. Then I attempt to turn on the running lights, and they flash and then nothing.

Several years ago I rewired the boat and put in a fuse block. The Garmin also has a switchable power supply. I also have a Perko switch with the two batteries.

My inclination is to start with the wiring to the fuse block, although everything else (dashlights, etc) work. The engine starts fine, but that is direct to the battery. I also wonder if it is ground related. My bet is tomorrow, after the boat sits in the garage and drys out overnight, the lights will work again. That is what happened the first night.

So, all you wonderful Sherlocks out there, where would you start and how would you proceed? Wiring isn't my strong suit, but I know enough to be dangerous.

Thanks,

Mick
 

DianneB

Petty Officer 1st Class
Joined
Feb 8, 2010
Messages
303
Re: Electrical Detectives..Put on your thinking cap

Sounds like a poor connection in either a 12 volt feed or a ground wire.

Try to figure out which circuits cause problems and start tracing the wires they have in common - turn something on in that circuit and go along wiggling wires in that circuit.

My first guess would be that one of your new crimp connections is not making good connection.
 

seabob4

Lieutenant Commander
Joined
Jun 10, 2008
Messages
1,603
Re: Electrical Detectives..Put on your thinking cap

Sounds like a poor connection in either a 12 volt feed or a ground wire.

Try to figure out which circuits cause problems and start tracing the wires they have in common - turn something on in that circuit and go along wiggling wires in that circuit.

My first guess would be that one of your new crimp connections is not making good connection.

Check the main feed going from your batt switch to the fuse block, and the ground from the batt (or ground bus) to the ground bus under your helm. One of those is making an intermittant connection...
 

MickLane

Cadet
Joined
May 6, 2004
Messages
19
Re: Electrical Detectives..Put on your thinking cap

Thanks, Dianne. I am thinking along those same lines. I will be heading to the garage to check it out. The only thing that bugs me about that scenario is the fact that the lights worked fine in the driveway yesterday. They also worked when I hooked up the water supply and started the engine in the driveway. But when I put it in the water, everything quit working. But that still leads me to believe a short of somekind. I will keep you posted. I really don't want to work in the 90+ degree heat, but off I go.

Any other ideas?

All the best,

Mick
 

MickLane

Cadet
Joined
May 6, 2004
Messages
19
Re: Electrical Detectives..Put on your thinking cap

Hi Bob. Thanks. I will start there. I will let you know the results.

All the best,

Mick
 

seabob4

Lieutenant Commander
Joined
Jun 10, 2008
Messages
1,603
Re: Electrical Detectives..Put on your thinking cap

The ride down the road on the trailer is probably what did it...
 
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